Soil phosphorus sorption saturation (Psat) measures the degree to which soil phosphorus (P) sorption sites have been filled and has been found to be a good indicator of P availability to runoff and leachate. At present, analytical methods required to estimate Psat are generally not offered by soil testing laboratories. This study evaluated the use of Mehlich-3 data in estimating Psat in a wide range of soils. In acidic soils Psat estimated from Mehlich-3 P, iron (Fe), and aluminum (Al) was highly correlated with Psat estimated from ammonium oxalate data as well as with a reference Psat estimated from bicarbonate P and the Langmuir sorption maximum In alkaline soils Psat estimated with Mehlich-3 P and calcium (Ca) was highly correlated with the reference Psat and the strength of that correlation improved only slightly by factoring in soil clay content Results indicate that Psat may be effectively estimated from Mehlich-3 data across a wide range of soils. This study confirms that Psat may be readily estima...